Procedure on MMF:
1 Take 200 g marshmellow in a bowl and add 2 tablespoons of water.
2 Insert in the micro until they are inflated/melted. (If you don't have mirco, read tips further down)NOTE: You must be looking, because this can go fast!
3 When the marshmallows is finished, stir and add the icing sugar until
you manage to make a "lump" of it. If you want the whole fondant in same color, please add the food coloring now. Wrap it in plastic when you're done.

This is where you can choose to go two different ways.

You can leave the MMF in the fridge for as long has you want, has long as you keep it completely sealed. NOTE: Leaving it over night will also make the color on the fondant stronger.

Let it cool down in the fridge at least one hour before use. I will not recommend start using it right away, when its all soften and difficult to work with.

Tips:

If you don't have a microwave, don't worry. Just use a bowl above a saucepan with boiling water. It would take less time, but has long as the marshmallows are getting melted that's the main thing!

When you're going to make the cover of the cake or do some decorations, use corn starch to prevent it from getting sticky. It's very easy to just brush off, and it doesn't leave any taste on the fondant. If you cant brush it off, due to small details like rose leaves and such, just use a paintbrush with a little bit of water on.

When you want to use it, you can either take it out and and let it soften on the kitchen bench, or you could start working on it right away. It's very hard, but just keep working on those muscles, hehe!

If you want to make decorations like flowers and so on, the dryness take around 2-5 days depending on the thickness on the fondant. I would recommend buying CMC and add to the fondant. This would make the fondant dry faster.

If you want to save it for more then one week, I would recommend sealing in the plastic as well has a completely sealed box in the fridge. This would make it last even longer and even up to 2-3 months.

When all done with the covering and the decorations on the cake, keep the cake in the fridge, but place it in rom temperature around 15 min until its ready to be placed on the table. DO NOT have food in the fridge which can transmit the smell over to cake, such as onions and other vegetables and food. If you have a plastic cover in hard materials, which would not destroy the cake or decorations, then it's brilliant, use it!